A consumer gas range typically includes, in addition an oven compartment and possibly a boiler compartment, surface gas burners to allow cooking on the range top. Conventionally, these surface burners are controlled by a twist type valve which regulates the amount of gas which is delivered to the burner, and hence the size of the resulting flame. Once the gas has been delivered to the burner, it exits, in a conventional type burner, through multiple ports around the outer periphery of the burner. This gas is then ignited to form a plurality of flames which are used to heat the bottom surface of the pot or pan placed on the grate above the burner.
The construction of one of these conventional burners includes a burner base having a plurality of upwardly projecting salients. A burner cap, which may also include a plurality of downwardly projecting salients which mesh with the upwardly projecting salients of the burner base, is placed on the base to form a plurality of gas outlet ports through which the gaseous fuel exits. As described above, this gas is ignited, resulting in the cooking flame. Alternatively, the burner cap may not include downwardly projecting salients, and instead may simply be set on the uppermost horizontal surfaces of the base salients, forming the uppermost wall for the plurality of outlet ports.
Regardless of the particular construction of the conventional multiple port burner for a gas range, the design and manufacture of these multiple port burners carry with it a high manufacturing cost. This is the result of the manufacturing requirements for forming a plurality of upwardly projecting salients for the burner base, and possibly the formation of a plurality of downwardly projecting salients for the burner cap. Alternatively, if either the burner base or the burner cap is utilized to form the entire port, the associated manufacturing cost of forming these ports within the outwardly peripheral wall of either the base or the cap is also prohibitively high.
Additionally, these plurality of outlet ports may in fact reduce the useable life of the burner because of the reduced size and wall thickness of these elements. Furthermore, the use of such salients are subject to breakage during the manufacture, assembly, and use of the range which also potentially shortens the effective life of the burner. Moreover, the use of a plurality of flames reduces the efficiency of the burner by distributing the cooking flame to a plurality of discreet points on the cooking surface. Additionally, for designs which utilize either upwardly or downwardly projecting salients, user error in replacing the burner cap after cleaning to properly form the plurality of outlet ports may contribute to increased risk of accident in the home.
One method of overcoming the efficiency problem of heating in a point-wise fashion with a conventional multi port burner, is to utilize a burner which produces a ribbon type continuous flame around the outer periphery of the burner cap. This single continuous flame provides a more efficient delivery of flame to the cooking surface in a continuous, not point-wise, fashion. One such burner design producing a ribbon type flame is described in U.S. Pat. No. 3,213,920 issued to Hoff on Oct. 26, 1965, for a GAS BURNER. This patent describes the design of a gas burner having a frusto-conical shape outer wall. A cylindrical sleeve is removably positioned within the frusto-conical outer wall to form an inner wall of the burner. Gas is delivered to this area between the frusto-conical outer wall in the removably seated cylindrical sleeve and flows to the reduced end of the outer wall through a narrow exit passage formed between the termination of this outer wall and the removably placed cylindrical sleeve.
This exit passage forms a continuous opening around the periphery of the burner. The top of the removable sleeve includes a deflector section having stepped horizontal walls which serve to deflect the exiting gas outwardly prior to ignition. These stepped horizontal surfaces are positioned such that the continuous exit port around the periphery of the burner has an outwardly increasing cross-section as the gas moves in stepwise fashion from one horizontal wall to the next stepped change horizontal wall. This stepped change in the deflector section is described as being required to prevent flame lift during high gas flow rates, and to prevent flash-back during low gas flow rates.
While such a design is described as producing a ribbon type flame which overcomes the efficiency problems of a multi port gas burner, the particular design of the Hoff '920 patent would appear to suffer from high manufacturing costs, and possibly reduced reliability. Specifically, the cost of manufacturing such a burner including the specific geometry burner base, the removable sleeve, and the deflector cap attached to the top of the removable sleeve increases the cost of manufacture. Additionally, such a design requiring a specific geometry on the deflector cap defining varying cross-sections in relation to the burner base also increases the risk of accident if misplaced by a user after cleaning. Additionally, since the removable insert forms the inner wall, misplacement of this insert after cleaning may increase the risk of accident due to unintended flow of gas through openings within the inner wall caused by misplacement of the inner sleeve. Additionally, such a design requires external ignition of the flame because of the requirement for a very small inner platinum to control the rate of flow therethrough. Such a burner is not compatible with the new sealed hob burner environment used in the newest designs for consumer gas ranges.